Externally-operated safety switch



1,623,573 Aprll 5, 1927. T. A. BOTH EXTERNALLY OPERATED SAFETY SWITCH Filed JulyS, 192:5 3 Sheets-Sheet 1 I i Q a INVENTOR.

1 BY a M A TTORN E YS.

A ril 5, 1927.

T A. BOTH EXTERNA LLY OPERATED SAFETY SWITCH Filed Jul'y5, 1923 3 Sheet s-Sheet 2 INVENTOR.

ATTORNEYS.

1,623,573 Aprll 5 1927. T. A. BOTH EXTERNALLY OPERATED S-AFETY SWITCH Filed Jul.v5, 192s s sheets-sheet s IN VEN TOR.

ATTORNEYS.

Patented Apr. 5, 1927.

UNITED STATES PATENT OFFICE.

TONJES A. BOTH, OF STBATFOBD, CONNECTICUT, ASSIGNOR TO THE CONNECTICUT 1 ELECTBICMANUFACTURING COMPANY, OF BRIDGFEORT, CONNECTICUT, A COB- PORATION OF CONNECTICUT.

EXTERNALL Y-OPERATED SAFETY SWITCH.

Application filed m 5, 1922. Serial No. 649,492.

This invention relates to a safety switch particularly for use in" connecting or disconnecting house or factory lighting systems with the supply mains, and has for an object to provide a switch and safety fuses which are enclosed in a protective casing or cutout box with means accessible from the exterior of the casing for operating the switch, and so arranged that access cannot be gained to the switch or fuses until the switch has been opened.

It is also an object of the inventionto so arrange the elements that the switch will be locked in open position until the protective casing for the switch and the fuses is closed.

' It is a further object of the invention to provide an improved operating mechanism for this type of switch, and one in which there will'be snap operation of the switch, and should the spring for giving the snap operation break, it Wlll be prevented from falling onto the switch contacts and causing a ground or short circuit.

It is a further object of the invention to provide a device of this character inwhich the switch may be locked in open position by means which may be operatedonly by authorized persons, such as representatives of the lighting company.

\Vith the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawings, in

which Fig. 1 is a top plan view of the switch and protective casing both being shown in the open position.

Fig. 2 is a transverse section upon line 22 of Fig. 1.

Fig. 3 is a transverse section immediately in front of the switch operating mechanism with the spring removed, the section being taken substantially on line but showing the elements in the positions they occupy when the switch is closed.

Fig. 4 is a detailed section substantially on line 4-4 of Fig. 3.

Fig. 5 is a similar sectional view through the center of the switch operating mechanism. i Fig. 6 is a plan and transverse section of the operating plate of the mechanism.

Fig. 7 is a plan and side elevation of the locking plate.

substantially 27 secured 3-3 of Fig. 1,

Fig. 8 is a plan and side elevation of the locking lever.

' Fig. 9 is a front elevation of the stop yoke.

Fig. 10 is a bottom plan view thereof.

Fig. 11 is a front elevation of the switch kickoff device, and

Fig. 12 is a side elevation thereof. The switch and the fuses are enclosed in a casing or cutout box 10, preferably made of sheet metal, open at one side which is closed by a door or cover 11, preferably hinged to the box, as shown at 12. When the cover is closed the box is closed completely enclosing the switch and the safety fuses. The fuses and the switch contacts are mounted on an insulating block or base 13 secured in the casing as by suitable screws 13. In the present instance 'the switch disclosed is a three blade knife switch, the three blades being shown at 14 pivoted at 15 to stationary elements 16 mounted on the base 13 by suitable means such as screws 17. These blades 14 are adapted to be swung on their pivots to and from engagement with the stationary spring contacts 18. base, as by screws the contacts Also mounted on the 19'and connected with to leads 22 from the power mains. The stationary elements 16 to which the switch blades are pivoted are connected by conductors 23 to spring contact clips 24 for one end of the safety fuses shown at dotted lines 25 in Fig. 1, these clips being secured to the block or base 13 by screws 26. The other end of the fuses engage similar spring clips 7 to the base by screws 28 and electrically connected by conductors 29 to the binding posts 30 to which the leads31. to the house wiring system are connected.

The switch blades 14 are each connected, to an insulating rod 32 as by suitable screws 33, and to this rod intermediate the connections thereof to the blades is connected a substantially U-shaped operating bar 34, the connections from this bar to the rod 32 being shown at 35. The bar 34 has at one end an outwardly extending pivot 36 extending in a bearing in the casing, and at its other end a similar pivot 37 extending into a r0- tary block 38, this rod being adapted to turn elative to the block, and the pivots 36 and 18 by suitable conductors 21,. are binding posts 20 adapted for connection with 37 are preferably substantially in alignment the pivots 15 for the switch blades 14. It will be apparent that by swinging bar 34 on its pivots the switch blades may be moved to and from engagement with the clips 24 to close and open the switchrespectively.

The arm 39 of the U-shaped bar 34 swings between the side arms 40 of a yoke 41 secured by suitable means as screws 42 to the inner surface of one side of the casing 10, and these arms 40 provide stops for limiting the movement of the bar 34 in opposite directions as it swings on its pivot. The yoke 41 is also provided at its opposite ends with fingers 43 and 44 forming stops to limit the movements of the switch operating handle or lever 45, as will presently be described.

The switch operating handle or lever 45 is located outside the casing 10 so that the switch may be operated without opening the box. This lever is secured to the block 38 4 so that by swinging the lever the operator may rotate this block, and this block is mounted in a side wall of thecasing. It comprises preferably a cylindrical element extending through this side wall, and has a central bearing for the pivot 37 on the bar 34' as described above. Mounted on this block on the inside of the casing are the operating plate 46 and the locking plate 47, the locking plate preferably having a circu lar opening 48 to' receive this block, but the block is provided with one or more grooves 49 to receive the operating plate 46, this plate being provided with a slot 50 to receive the portion of the block between the grooves as shown at Fig. 6, so that the plate 46 will rotate with the block. The plates 46 and 47 are connected together so that plate 47 will also rotate with the block. For this purpose plate 47 is provided with a notch 51 adapted to receive a lug 52 struck laterally from plate '46. When assembled spring washers 53 are mounted on the block 38 on opposite sides of the casing wall, and one or both of them may be slightly concaved so as to take up any lateral play of the block in the casing. In assembling the plate 47 is placed on the block and then the plate 46 is slid laterally into the grooves 49. These grooves not only cause the plate to rotate with the block, but also retain the'plate against longitudinal movement on the block and secure the elements in assembled relation.

Carried by the plate 46 is a spring pin or stud 54, this pin being preferably secured to the plate by riveting one end in the opening 55, and this pin is grooved adjacent its outer end, as shown at 56, to receive one of the spring connecting elements 57, the other spring connecting element 58 being seated in a similar groove 59 in the bar 34. The operating spring is shown at 60 and is illustrated as a coiled compression spring, but

the effect of the spring is to draw the elements 34 and 54 together. The ordinary construction would be to use atension spring. Tension springs ire'much more liabletto break in operation than a compression spring, and should the tension spring break it would be liable to fall onto a live switch contact and cause a short circuit or ground. To prevent this I mount the spring as shown, extending the spring connecting elements 57 and 58 longitudinally through the spring and provide hooks 61 and 62 engaging the opposite ends of the spring which are also the ends of the spring respectively more remote from the connection 6f these elements to the bar 34 and spring pin '4. Thus it will be seen that the effect of drawing the elements 34 and 54 together is secured by a compression spring mounted between them,

but there are always supporting elements extending throughout the length of the spring, so that should the spring break, these supporting elements will prevent the spring dropping onto any live switch contact and causing a short circuit or ground. The spring 60 also retains plate 46 in position on lfilock 38. Thus if the spring is disconnected rom disassembled.

Pivoted to the yoke 41, as by a screw 63, is a kickoff device 64 which is forked at its opposite end as shown at 65, to'receive the spring stud 54, this stud being preferably provided with a circumferential groove 66 to receive the sides of this fork. Intermediate its ends this kickofi' device is provided with laterally extending kickotl' lugs 67 extending on opposite sides of the arm 39 of the bar 34.

In operating the switchrit will be apparent that rotation of the block 38 by the lever 45 will rotate plates 46 and 47, and cause the pin or stud 54 to swing about the axis of this block, that is about the axis of the pivots for the bar 34 and the switch blades. The movement of this pin will swing the connection of the spring thereto through the same are and will carry the axis of the spring through the line joining the center of the bar 34 with its pivots 36 and 37. It will be apparent that movement of the pin 54 on an arc from one side of this line to the line will compress the spring by increasing the distance between the bar 34 and the pin 54, but the pull of this spring during this movement will hold the bar 34 and the switch blades stationary with the arm 39 against one of the stops 40. But as soon as the pin 54 passes beyond the line, the pull of the spring will move the rod 34 about its pivot and will operate the switch with a snap action.

As the pin 54 is swung under this operation its connection with the kickofi device pin 54 the plate 46 may be removed. from the block allowing the elements to be 64 will swing this'device on its pivot, and will bring one 'of the in s 67 into engagement with the side of t e arm 39 of the bar 34, these lugs being so located that they ing lever engaging arm the free edge of the door or cover 11 will engage the arm before the pin 54 passes through theline joining the center of bar 34 with its pivot, and so will start to move the bar 34 before the spring is in position to move it, thus giving a positive direct action from the lever to the bar 34 to give it its initial movement independent of the spring. The lug 67 on the under side of. the arms 39 which gives initial movement to the bar in opening the switch is so arranged that should the spring break still give enough movement to the bar 34 to open the switch, but the other lug (37 is so locatedthat should'the spring break it cannot close the switch. The lockingplate 47 is also provided with oppositely extending arms 78 adapted to engage the stop fingers direct-ions when the switch mechanism is operated.

For the purpose of locking the switch open when the casing door is open and for locking the door closed when'theswitch is closed, there is ivoted inthe casing- .on the sidewall with tii nism, a locking lever 68. 1 This lever is pivoted to the sidewall at 69 and a't its lower or inner end is provided with a laterally extending lug 70 adapted under certain conditions to enter a recess 71 in the periphery of the locking plate 47, and at its other. end is provided with a fork having two fingers 72'and 73. A sprin 74 is mounted on the pivot for this lever liaving one end 40 and its other end 76 secured to the lever as by passing thro'u h a loop 77. This spring tends to swing t e lever about its plvot counterclockwise, as viewed in Figs. 2 and 3 to hold the lug 70 against the locking plate 47. Carried by of the casing is' a pin 79 adapted when the cover is in closed positiom to engage the lower finger 72 of the locking lever to swing this lever on its pivot in a clockwise direction, as viewed in Figs. 2 and 3, and move it to the position shown in Fig. 3. When moved to this position the locking lug 70 on the lever 68 will be moved out of the locking recess 71 carried by the plate 47 and thus it will be apparent that when the door or cover is closed the switch may be operated in either direction by swing'in the lever 45. The recess 71 is so located: however, as to be in alignment with the lug 70, as shown in Fig. 2, only when the switch is in its open'position. When the cover is closed and the lockswung to the position shown in Fig. 3 by the pin 79, the upper finger 73 on the locking lever is swung over the top of it will- 43 and 44 to limit movements of this plate and the operating lever 45 in opposite e switch operating mechathe pin 79 on the cover, as shown in Fig. 3. .If now, after the cover is closed, the handle 45 is moved to operate the switch to closed position it will be apparent that only a slight movement ofthis handle will move thenotch or recess 71 away from ali nment with the lug 70 and that, therefore, t is lug will engage the periphery of the plate 47 and-prevent swinging of the lever 68 on, its

pivot and thus, at all times, except when the switch is'open and the lever 45 is swung to the extreme open position, the lever 68 is held against movement by the engagement of lug 70 on the periphery of plate 47. Therefore, as soon as the lever is moved from the extreme position shown in Fig. 2 the reaction of finger 73'on pin 7 9 will lock the cover in closed position, and thus the only time in which the cover may be opened is when the switch is open and the lever swung to this extreme position. It will also be apparent that should be cover be opened when "this switch-is in the open position, immediately the pin 79 is moved away from finger 7 2 the locking lever 68 will be swung on its pivot by the spring 74 to 'move lug 70 into recess 71 and lock the switch in open. position. Therefore, while the cover is opened the switch is locked open. .1 If the lighting company wishes to prevent closing of the switch for any reason, as when service is discontinued, means is provided for locking the switch in open padlock 83 extending through the eye 84, it will be apparent the switch cannot be moved to closed position until the box has first been opened and the locking plate 80 removed from engagement with the pin as. For holding this plate against accidental IUD done the cover is closed andlocked by any suitable means, such as a movement in either its on or off position, it n is preferably provided with an opening 85 adapted to receive either of a pairof projections 86 struck up from the wall of the The eve 84 casing one for each position.

passes through the when thevcover is closed slot 87 therein.

From the foregoing apparent that the construction is very simple and will be perfectly reliable in operation. It will also be apparent that the only time the switch may be operated is when the cover of the casing or box is closed. that as soon as the cover is opened the switch is description it will be locked in openposition. Also, that after the cover has been closed and the switch moved toclosed position the cover cannot be open until the switch has been opened. Therefore, should a fuse be blown, access cannot be had to the box to renew the fuse until the switch has been opened, and thus there will be no danger in removing the old or inserting a new-fuse.

It will be still further apparent that the lighting companymay open the switch by swinging the lever, lock it in the open position by means accessible only from the interior of the box and then lock the box, and therefore, the servicemay be discontinued without disconnecting any of the service connections. Also after the service has been discontinued it can be quickly and easily restored by an authorized person, by merely unlocking the box and then unlocking the switch, by swinging the locking plate 80. If then the box is closed the switch may be swung t0 the closed position.

Having thus set forth the nature of my invention, what I claim is:

1. In combination, a pivotally mounted switch blade, a compression spring, a movable support, means connecting the switch and the support with the ends of the spring respectively more remote from said elements comprising substantially U-shaped wire members connected to said elements at their closed ends and extending through and enclosed by the spring, said members being provided with hooks at the free ends of their side arms to engage the opposite ends of the spring, and means for moving the support to pass the spring through the axis of the switch blade to operate said blade.

2. In combination, a pivotally mounted switch blade, a pivoted bar connected with said blade for operating the same, a compression spring. a movable element, means connecting the bar and said elementwith the ends of the spring respectively more remote from said elements comprising substantially U-shaped wire members embracing said bar and element at their closed ends and extending through and closed by the spring, said members being provided with hooks at the free ends of their side arms to engage the opposite ends'ot' the spring, and means for moving the said element to carry the spring past the pivot for said bar to operate the switch.

3. In combination. a movable switch element, a movable element, a coiled compression spring substantially U-shaped wire members connected to said elements at their closed ends and extending through and enclosed by the spring, said members being provided with hooks at the free ends of their side arms to engage the opposite ends of the spring, and means to swing said element on an arc to compress the spring andas it passes by a line passing through the center of said arc to allow it to expand and operate the switch.

4. In combination, a movable switch element, a rotatable operating element having one or more transversely extending grooves, a forked operating plate adapted for sliding engagement in said grooves. and an operating spring connected to said switch and said plate and adapted to retain the plate on the operating element.

5. In combination, a movable switch element, a rotatable operating element having one or more transversely extending grooves, means for rotating said element, a locking plate mounted on said element to rotate therewith and adapted for longitudinalmovement thereon, a forked operating plate adapted for sliding engagement in said grooves and to retain the locking plate against longitudinal movement, an operating sp ing connected to said switch and the operating plate and adapted to retain the plate on the operating element. and locking means adapted to engage the locking plate to retain the operating element against rotation.

6. In combination, a casing, a pivoted switch element in said casing, a yoke secured to the casing and having spaced stops. a bar secured to the switch element for operating the same and pivoted so as to swing between said stops, a rotatable operating means. a spring connected to said bar and said rotatable means for operating the switch, a plate pivoted to said voke and having connection with said rotatable means whereby the plate may be swung on its pivot, and lugs carried by said plate on opposite sides of the bar and adapted to engage the same to impart initial movements to the switch element.

7. In combination, a pivoted switch element, a pivoted ba'r secured to the switch element for operating the same, a movable operating means, a. spring connected to said bar and operating means for operating the switch, a pivoted plate connected to said operating means so as to be swung about its pivot, and. means carried by said plate adapted to engage the bar on opposite sides thereof as the plate is swung on its pivot, said means being so located as to be capable of opening the switch should the spring break but incapable of closing the switch.

In testimony whereof I atfix my signature.

TONJ ES A. BOTH. 

